Methylene

[Sarah]

A hydrocarbon radical, CH2, not known in the free state, butregarded as an essential residue and component of certain derivativesof methane; as, methylene bromide, CH2Br2; -- formerly called alsomethene. Methylene blue (Chem.), an artificial dyestuff consisting ofa complex sulphur derivative of diphenyl amine; -- called also pureblue.